Montana Resources prepares for highwall failure in Continental Pit

In late August, Montana Assets detected instability within the east highwall of the mine’s Continental Pit. Since then, the highwall has continued to maneuver.

“It’s accelerating,” mentioned Mark Thompson, the mine’s vice chairman of environmental affairs, throughout a Thursday interview.

“Day by day it creeps about one-half an inch,” mentioned Mike McGivern, vice chairman of human assets and security for Montana Assets.

The east highwall of the sprawling open pit copper and molybdenum mine in Butte isn’t removed from Interstate 15. However when a portion of the highwall crumbles or collapses it is going to tumble in the other way.

Thompson mentioned Montana Assets needed to alert Butte residents that the east highwall was unstable in case they witnessed its failure from afar and jumped to conclusions about security dangers to mine staff.

“We’re utilizing very subtle gear to observe the state of affairs and we’re managing it in a protected and accountable method,” he mentioned.

The monitoring gear consists of radar and “slideminder” detection expertise whose knowledge about motion of the highwall are tracked by Montana Assets staff and consultants.

Thompson mentioned consultants really useful creation of a “runout” zone that will be greater than 300 toes from the bottom of the highwall to maintain staff and gear at a protected distance. He mentioned Montana Assets determined to extend the security issue by constructing a berm 500 toes from the foot of the rockface.

A deep, serpentine and ominous crack is seen on the high of the highwall. Thompson mentioned the highwall’s instability is certainly the results of energetic mining. There may be excessive worth copper ore towards the bottom of the highwall, he mentioned.

The mine want to return to mining this ore.

“We’d love the highwall to fail by itself,” Thompson mentioned. “It may very well be a major failure. It may very well be a partial fail.”

Regardless, Montana Assets will ultimately want to handle the highwall’s potential for instability by creating a brand new headwall with a flatter slope. In preparation for that work, the mine is starting work adjoining to I-15 that may yield a ramp for heavy gear.